When to replace shingles?

We have been in our present home almost ten years and see no obvious
problems with the roof, except that there seems to be an enormous amount
of grit in the gutters.
We have no idea when the current shingles were installed, so how do we
tell when it's time to replace them? The previous owners left a few
spare shingles but, apart from the marking "CertainTeed Roofing
Collection" and a series of <letter>1234 markings along the anti-stick
tape, these seems to be no way of knowing how long they could be
expected to last.
Obviously, waiting until the roof starts leaking is not a good idea.
Perce

I don't see any curling -- unlike the severe curling on the shed roof
before I replaced the shingles about three years ago.
The Web page to which you referred talks about "more grit than normal"
(or words to that effect) -- but what is normal? There is much more grit
in the gutters on the SW-facing side than on the NE-facing side. But
even the SW-facing side still looks its normal color.
How long do shingles typically last? Or is that a "How long is a piece
of string?" question?
Perce

I keep looking at my roof because it is at or near the end of the 25
year warranty period. Still looks good and while there is always a
little grit in the gutters when I clean them it does not appear
excessive. My first roof in the house when new only lasted 15 years.
Builder had, what I believe is called winging, by saving on nails. I
think they were 20 year warranted but builder had voided it with
improper installation.
I guess if your shingles are not curling or roof does not leak you
should be OK for the time being.

I don't think the amount of grit is a reliable indicator.
Signs of curling, cracking, being brittle, is what I'd
look for. Especially the cracking. When it's at EOL,
you'll start to see cracks in the shingles, pieces breaking
off, even though there are no leaks.
I had a numbskull that I used to work with that built
houses on the side. He looked at my roof from the ground
one time and told me I needed a new roof. 15 years later,
the roof still wasn't leaking, but needed to be replaced
because of damage from Sandy. At that point it was finally
starting to show signs of cracking.

Be sure to look at the southern side, or the side closest to the
equator. With a pitched room, it gets more sun. I can't see that
side of my roof from the ground, but I can see the northern side,
which looked fine even when the southern side looked like a little
girl's curls.

I have a friend who was married to a physical therapist. I sat down,
and lifted and folded my legs -- they fold better than most other
people's, so that one calf and foot is entirely on top of the other,
and the top knee is resting on other foot -- and she told me if I sat
like that, I'd need physical therapy. Now it's more than 20 years
later and it's still the most comfortable position I have.
I don't know aobut your friend but I give her a little bit of the
benefit of the doubt that if she sees people all day long that need
physical therapy, she forgets what regular people are like. But for
other reasons she was a real ding-a-ling, crackpot, and obnoxious too.

Generally, as long as your shingles are laying flat, your roof shingles
are still in good condition.
The granules on the top surface of the shingles are intended to protect
the asphalt the shingles are made of from the UV light from the Sun. As
that asphalt deteriorates, not only do the shingles start to lose
granules, they start to curl into distorted shapes.
Here's a couple of roofs where you see that the shingles are just
starting to curl. Both of these roofs still have a good 5 years of life
in them, if not more.
http://tinyurl.com/lxx5kca
http://tinyurl.com/mfsujvj
If the shingles on the above two roofs aren't replaced, then the curling
will continue to get worse. When you see shingles that look like this:
http://tinyurl.com/k2wt23c
Then the roof is at the end of it's life.
And, if the shingles still aren't replaced, you can end up with shingles
that look like this:
http://tinyurl.com/ln53zeg
And, at that point, it's possible that some of the roof sheathing has
rotted under those curling shingles and the homeowner would incur
additional costs to have that rotted wood replaced.
If there are trees in your yard and the tree branches rub on your roof,
it's a good idea to prune those branches. Otherwise the branches can
brush the granules off the shingles and shorten the lifespan of those
shingles.

I would only point out that a roof in that condition is
extremely vulneable to storm damage. Get a wind storm in the
right direction with enough force and it will tear off those
shingles, then the ones beyond it, etc. Now you have water
pouring in, exensive damage and an emergency. Instead of
replacing the roof when you want, at the right price, etc,
you may be doing it when you have few choices.
How lucky do you feel?
I would never let a roof get even close to the state of that
pic before replacing it.

During my college years, I worked for over a year at Malarkey Roofing in
Portland Oregon. Picked thousands of three-tab shingles from the shingle
machine.
The roofing shingles are made from thick wood based felt that is first
saturated with really hot asphalt. Then coated on both sides with
thicker, hot asphalt. The back side is coated with mica dust to keep it
from being sticky, and the front surface is coated with a pattern of
colored stone granules. The material then goes through press rollers to
firmly imbed the granules in the hot asphalt. After cooling, the sheet
goes through a die cutting machine, which produces the shingles. That is
where I worked.
The grit or granules are on your shingles to reflect as much heat and
light from the sun as possible. Light colored granules will protect the
shingle longer than dark colors. All asphalt evaporates and oxidizes
over time. This includes your highway paving, and your roofing.
Eventually all the asphalt coating will evaporate and you will be left
with the saturated felt, which will then evaporate and you will be left
with yellow/brown wood felt.
The roofing shingles will not leak until the asphalt is completely gone.
As the asphalt in the felt evaporates, the felt will shrink and cause
curling shingles.
The sunny side of your roof will loose it's granules first. Our previous
house had to have the ridge shingles replaced before the buyer your
complete the deal. They were of a different manufacturer from the
three-tab shingles. All the granules were off and the felt was showing.
the rest of the roof was fine and good for many more years. Both were
about 20 years old.
the loss of granules is a normal thing. Hail, heavy rain,
freezing/thawing, all contribute. Same thing happens if you walk on the
roof. Just watch for the felt to begin showing, or the color of your
roof changing to something you don't like. that will tell you to redo
the roof.
Paul

Same here. I had to replace my ridge shingles after 11 years.
But the rest of the shingles were still fine. The ridge shingles were
organic CertainTeed. There was a class action law suit about the
CertainTeed shingles, but I was too late on that.
The ridge shingles were curling, cracked and bare of rock in many
places.
Nice write-up on shingles. Thanks.

Thanks. when I was at Malarkey, we made 3-tab shingles for many
different companies. Certainteed was one of them. Same old stuff,
different wrapper! At that time, the U/L label id number was always
Malarkey's.
Paul

I just had a roof redone with Malarkey architectural shingles. The
roofer said they were $8 a square cheaper then the "name brand" that I
can't remember right now. He thought they were probably the same
shingles but with slightly different colored chips. From what you are
saying Malarkey is the maker of many brands and from what you know
they are all made the same on the same line?

I was remembering working there in 1961/63 time frame. Don't know
anything about the industry, know, but most consumer things are made by
other than the company on the label. Always has been and always will be.
Malarkey made several types of shingles than the three-tab ones. Just
changed the die roller in the shingle machine. One I remember was "Dutch
lap". They were trapezoid in shape. No tabs. I think the whole shingle
was a single color, not the "shadow" effect of the three-tab.
We used all different colors of granules. Came in hopper cars on the
railroad.
May have been other shapes, as well.
Paul

New shingles shed granules, so are we to assume the granules in the
gutters are a new development and not old accumulation? I'd first email
Certainteed with the number code and ask them. Can't contact the
previous owner or check for a building permit for roof install? Then
I'd go for how it looks....not curled, cracked or bare of granules?
Then I'd assume I might have another 10-20 years on the remaining
expected life of the shingles. Mine are new so I don't need to worry :o)

In my experience the only real reason to replace them is that the tabs
break off, usually during a wind storm. If you get there "in time"
before the next storm hits and use roofing tar to glue the broken tab
back down/back in place, or use new shingles, or suitable sizes pieces
of new shingles, and slide them under the existing ones and glue it
all down, you can make the roof last till almost ever last bit of
"grit" is gone from the surface. The key is repairing all the problem
areas as soon as they appear. Also, if the tabs are no longer glued
down, even if still good, you can save them by gluing them down. Most
recently they have started selling caulking gun style clear roofing
cement. Stick a tub in your caulking gun and it's easy to shoot glue
under any loose tabs and get them glued back down. And the clear
looks a lot better then black smudges for the repairs.

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